The subject matter of the invention relates to a speech simulator, auto actuatable switch therefore, and a method for simulating speech in tracheotomized patients, including quadriplegics.
The patient dependent on mechanical ventilation through a tracheostomy is unable to vocalize because of interrupted air flow to the larynx. An inability to communicate may compromise medical care and prove a source of extreme frustration and emotional stress to the patient. It is generally not feasible to disconnect the ventilator, deflate the cuff on the tracheostomy tube and occlude the tube to momentarily allow the patient to exhale around it for brief communication. Moreover, should the patient be a quadriplegic, written and gestural communications are impossible and lip reading or an elimination process of questioning both have their obvious limitations.
Electronic artificial larynges have been developed to provide rudimentary communication for tracheotomized patients. The most common artificial larynx is generally a hand held, battery powered instrument which emits a continuous high frequency buzz. The buzzing sound is transmitted through the neck into the mouth where it is modified by mouth and throat movements to produce recognizable speech like sounds. Difficulty is often encountered however, in placing the instrument effectively and securely against the skin of the mandibular triangle and coordinating sound production with speech articulation. Importantly, the quadriplegic patient remains dependent on others to anticipate when he wants to speak and to operate the artificial larynx.
Pneumatic artifical larynges have also been developed. The most common of these devices is the Tokyo artificial larynx which has a stoma cover connected to a mouth tube with a vibrator chamber therebetween. A modified version has a finger-controlled breathing port by the vibrator chamber. Both of these devices are hand-held and manually operable.
The obvious limitations inherent in the use of the artificial larynx by a tracheotomized quadriplegic led to the development of an auto actuatable device comprising a headband with an adjustable sliding arm which actuates a tone generator, the output of which is tubed to a patient's mouth. A sliding contact switch mounted on the forehead is utilized to activate the tone generator to produce sound for speech by the simple wrinkling action of the patient's forehead. This device has a major limitation in that the headband must be adjusted snuggly enough to stay in place, but not so tight as to restrict circulation. This often necessitates the use of a cotton sweatband or a light weight cap to increase comfort and to decrease skin irritation and slipping on oily skin or hair. Moreover, the location of the tube within the patient's mouth interferes significantly with the patient's ability to articulate. The opening to the mouth tube frequently fouls with saliva thus impeding speech production. Additionally, speech produced by this device is electronic sounding and this artificial quality is frequently rejected by potential users.
Alternative devices have also included the Pitt "Speaking Tracheostomy Tube" and the Portex "Trach Talk" which comprise tracheostomy tubes having a narrow gauge conduit incorporated into their convex surface that terminates at a fenestration slightly above the inflatable cuff. An external air flow can be delivered to the larynx through this conduit independent of the oxygen being supplied to the lungs by mechanical ventilation. This is accomplished manually by the patient occluding a "Y" connector attached between the narrow gauge conduit and a source of compressed air. In so doing, sufficient air flow is provided the patient such that an audible whisper might be produced.
In practice, it has been found that the location of a fenestration through which compressed air is delivered to the larynx is situated too close to the tracheostomy, thereby allowing air to escape out and around the tracheostomy tube. This results in decreased air flow for speech and an annoying hissing noise at the neck. Furthermore, patients have frequently reported that air flow reaching the larynx tickles or gags them if for example, the flow is directed in too narrow a stream. It has been shown that patients on a ventilator frequently have laryngeal and supra-laryngeal tissue changes secondary to traumatic intubation. In many instances these tissue changes interfere with adequate air flow for voice production in patients with whom the "talking trach tubes" are tried. Finally, and most importantly, quadriplegic patients who can achieve audible speech with currently available speaking tracheostomy tubes still remain dependent on others to anticipate when they want to speak and to operate an external air flow.
It would therefore be highly desirable to provide an improved speech simulator and a method for simulating speech for tracheotomized patients.
It would also be highly desirable to provide an improved auto actuatable speech simulator and method which allows oral communication with, and readily intelligible speech by, a tracheotomized patient.
It would also be highly desirable to provide an improved auto actuatable speech simulator and method which allows oral communication with, and readily intelligible speech by, a tracheotomized quadriplegic patient.
It would be further highly desirable to provide an improved auto actuatable speech simulator and method which can be switched on and off by hand, if possible, or by an improved forehead mounted switch by quadriplegic patients.
It would be further highly desirable to provide an improved speech simulator and method which provides for the introduction of air through a nasal catheter which does not bother the patient, interfere with the patient's speech or produce unwanted noises or physical sensations during use.
It would be further highly desirable to provide an improved speech simulator and method which provides for a non-electronic, more natural sounding simulated speech by a tracheotomized patient.
It would be further highly desirable to provide an improved speech simulator and method which provides a device which may be simply and inexpensively produced.
It would be further highly desirable to provide an improved speech simulator and method which requires no assistance and, little, if any, instruction of the tracheotomized patient to operate.
It would be still further highly desirable to provide an improved speech simulator and an auto actuatable switch therefore which can be used by a quadriplegic or even the most severely paralyzed patient.
It still further highly desirable to provide an improved auto actuatable switch for use by a quadriplegic which has no moving parts and is comfortable to wear.
It would finally be highly desirable to provide an improved auto actuatable switch for use by a quadriplegic which is simple to use, and may be utilized to operate any electrically actuatable device.